The idea here is to identify controls by their intended use rather than their names. For example, a given device may have a control that is commonly used to trigger a "submit" style of command. It would indicate that by assigning the "Submit" usage to the control.

Assignment of usages is currently handled at the device level. For example, the Keyboard device by default assigns the "Back" and "Cancel" usage to the escape key whereas Gamepad assigns them to the A/circle button by default.